A zipper tape that can be re-sealed after having been opened is utilized for a bag (package bag) for foods, medicine, and miscellaneous goods.
A conventional zipper tape is constituted by a male member having a male interlocking section and a female member having a female interlocking section which is fitted with the male interlocking section, each member being separately extruded before being attached to the bag in an interlocked state.
As a consequence, a conventional bag with the zipper tape has not exhibited satisfactory sealing performance, and further, it has been impossible for a user to confirm that the zipper tape has not been opened in advance or that the bag has not been tampered.
Thus, as a way of improving the sealing performance and preventing the tampering, a structure in which an opening of the bag is heat-sealed has been proposed. However, the structure bothers a user to cut the opening of the bag with a cutting tool, unless an easy means of ripping otherwise is provided.
One bag that has been proposed to allow the user to unseal without a cutting tool or the like is a package bag with a zipper tape disclosed in Patent Document 1 (see, Patent Document 1).
In this package bag with a zipper tape, a male member having a male interlocking section and a female member having a female interlocking section are separately molded from synthetic resins different from each other. The male and female members are heat-sealed onto an inside of the opening of the bag, and at the same time, the facing sides of the male member and the female member are bonded with a relatively small heat-seal strength.
Patent Document 1: JP-A-2004-155458